Process of coating corks with resisting neutral layers.



UNITED STATES PATENT OFFICE.

LEONHARID PINK, 0]? BERLIN, GERMANY, ASSIGNOR, BY MESNE ASSIGNMENTS, TODUTCH HOLDING COMPANY, A CORPORATION OF NEW YORK.

Y PROCESS OF COATING CORKS WITH RESISTING NEUTRAL LAYERS.

No Drawing.

Specification of Letters Patent.

Application filed January 26, 1911. Serial No. 604,889.

Patented Mar. 18, 1913.

To all whom it may concern:

Be it known that I, LEON HARD'PINK, asub ject of the German Emperor, andresident at Blumenstrasse 70, Berlin, Germany, have invented certain newand useful Improvements in Processes for Coating Corks with ResistingNeutral Layers.

This invention relates to a process for coating corks with resistinglayers for instance for the purpose of doing away with the interpositionof small. sheets of parchment paper.

This process consists in coating corks ready for use with a solution ofcellulose ammoniacal oxid of copper by dipping it into this solution orin any other manner, in removing the oxid of copper in the well knownmanner in a bath of sulfuric acid and in converting the coating in abath of sulfuric acid containing about to 60 per cent. of sulfuric acid.The separated cellulose or nitro cellulose is amyloidized by thesulfuric acid, forming a thin film or coating which extends somewhatinto the pores, of the cork. The oxid of copper is removed andsimultaneously the residue ofthe deposit on the cork is parchmentized bythe sulfuric acid. This coating of parchment when compared with corkswhich has for instance been impregnated with paraflin, has thisadvantage that it resists better mechanical influences such as rubbingand scraping and allows above all that the corks may be caused to swellin hot water before use, which is impossible with a paraiiin coating.

I claim:

A process of coating corks with neutral films adapted to increase theresistance against chemical and mechanical influences, consistingincoating them with a solution of cellulose in ammoniacal oxid of copperand then subjecting the coated corks to the action of sulfuric acid longenough for removing the ammoniacal oxid of copper and for parchmentizingthe cellulose deposited on the cork.

. In testimony whereof I have hereunto set my hand in presence of twowitnesses.

LEONHARD PINK.

Witnesses WOLDEMAR HAUPT, HENRY HASPER.

